I’m one step closer to working this out.
I’ve realised that the loop is displaying content as a page and I’m filtering it accordingly, what I should be doing, is displaying it as a single_post.
Putting $wp_query->is_single = true; in the header PHP has solved this issue. What it hasn’t done, however, is allow the index.php to be static, and display the previous post within itself.
If anyone could further this, I’d appreciate it.
Thanks,
Grant.